1. Field of the Invention
The present invention relates to an aqueous waste treatment method and apparatus that provides improved treatment of aqueous waste and, more particularly, to a method and apparatus which employs improved functionality, ease of operation and aeration techniques to provide improvement in the treatment of aqueous waste.
2. Background Information
Currently, the processes used in wastewater treatment plants follow traditional methods that expend energy, materials and labor at a relatively high rate along with a large use of land. The high costs associated with traditional methods of wastewater treatment are due to the treatment, handling, and monitoring of all of the wastewater flow""s components with equipment such as pumps, blowers, air compressors, scrapers, filters, chemicals, heat, presses, coagulants, flocculants, precipitants and dewatering, among others. In traditional wastewater treatment systems, the wastewater is treated using high-energy-consuming methods. These methods include, but are not limited to, aerobic digestion, anaerobic digestion, sludge thickening and solids dewatering processes. The costs associated with these treatments amount to approximately 85% of the plant operating energy budget.
In a typical influent wastewater stream which is subject to wastewater treatment, 99.9% of the entire wastewater stream is water and about 0.1% is organic, inorganic and dissolved solids. The typical influent wastewater stream also contains nutrients in varying concentrations. Nutrients within the wastewater stream which need removal have an oxygen demand which must be met for decomposition. In the industry, this oxygen demand is referred to as biochemical oxygen demand (BOD). Of the approximately 0.1% solids, about 10% to 20% are settleable solids containing about 35% of the BOD. The remaining 65% of the BOD is contained within the dissolved organic matter portion of municipal waste. See FIG. 13.
In the solids (sludge) handling systems of traditional wastewater treatment systems, processing energy is expended for organic matter to be reduced by digestion to a level of about 50% reduction in volume while the remaining 50% volume of organic matter is disposed of by a number of means including, but not limited to, landfill disposal, incineration and land application. This results in the expenditure of additional energy and expense for the handling of solids. It would be beneficial to have a system and method that eliminates most of the need for disposal of organic matter.
It is an object of the present invention to provide an apparatus and method for treating aqueous waste containing organic matter and chemicals.
It is another object of the present invention to use an activated sludge process with recirculation of a treatment zone and greater aerator effectiveness to decrease the time and energy necessary for decomposition of organic matter.
It is yet another object of the present invention to substantially reduce the wasting of organic matter in the form waste activated sludge (WAS), which is the intentional removal of organic settled solids from the system, and thus reduce the effort and cost of solids handling facilities.
It is another object of the present invention to provide an apparatus and method for treating aqueous wastewater that contains high concentrations of industrial type nutrients.
It is yet a further object of the present invention to treat municipal waste that has typical concentrations of chemical oxygen demand (COD), BOD, ammonia and phosphorus.
It is yet a further object of the present invention to treat industrial strength waste that has high concentration levels of COD, BOD, ammonia and phosphorus typically found in animal type wastes.
It is still another object of the present invention to provide an apparatus and method for pretreating wastewater from on-site facilities such as might occur from industrial manufacturers or animal wastes facilities.
It is another object of the present invention to utilize an efficient re-circulating aeration system (RCAS), which provides a combination of aeration, mixing, homogenizing and shredding that is superior to and is more affordable than conventional aeration systems.
It is still another object of the present invention to provide an apparatus and method that is easier to design, operate, construct, initialize, manage, expand and maintain than conventional treatment systems.
It is still another object of the present invention to provide an apparatus and method that is easier to adapt to changes in processing and flow conditions, and that is easier to automate, monitor and control than conventional treatment systems.
It is still another object of the present invention to provide an apparatus and method that when compared with similar wastewater treatment requirements, uses an overall smaller footprint (land area) than that found with conventional wastewater treatment plants.
It is still another object of the present invention to provide an apparatus and method that is more economical to operate than conventional wastewater treatment systems.
It is still another object of the present invention to provide an apparatus and method that is less expensive to build and operate than conventional wastewater treatment systems.
It is still another object of the present invention to provide an apparatus and method that increases the ability of the process vessels to treat larger quantities of wastewater in aeration basins by not being limited by vessel floor surface area for placement of diffusers with regard to the ability to deliver intense aeration.
It is still another object of the present invention to provide an apparatus and method that provides a significantly increased decay coefficient (kd).
It is still another object of the present invention to provide an apparatus and method that increases the mean cell residence time (MCRT) beyond that of conventional treatment systems, thereby providing for increased volatile solids destruction and subsequent reduced solids-handling efforts.
It is still another object of the present invention to provide an apparatus and method that allows for a highly flexible food-to-microorganism (F/M) ratio range above and below the ratio ranges of conventional treatment systems.
It is still another object of the present invention to provide an apparatus and method that reduces start-up costs, which include, but are not limited to, more rapidly increasing the mixed liquor suspended solids (MLSS) concentration, lower power costs for initial start-up and reduced costs for hauling of seed sludge, thereby achieving design flow capacity with increased efficiency.
It is still another object of the present invention to provide an apparatus and method that uses vessels for a type of sequential batch reaction system during start-up conditions for faster initial plant start-up.
It is still another object of the present invention to provide an apparatus and method that uses vessels for a type of sequential batch reaction that allows micro colonies to grow rapidly following conditions that have upset a process, so as to quickly grow microorganisms which recover from the upset conditions.
It is still another object of the present invention to provide a treatment plant that contains less apparatus and processes to treat the wastewater to the desired effluent quality than conventional wastewater treatment systems.
It is still another object of the present invention to provide a device that separates solids from liquid through clarification without the need for scraping, raking or brushing devices in clarifiers.
It is still another object of the present invention to provide a device that acts as a solids-capturing zone which includes, but is not limited to clarifiers, filtration structures and optional tertiary treatment systems that further capture organic matter, and that return the organic matter to aerobic zones for continued solids digestion.
It is still another object of the present invention to provide a device that decreases total nitrogen in a waste stream through oxidation of organic nitrogen into the more stable compound of nitrate, which is then reduced in the waste stream by the denitrification process.
It is still another object of the present invention to provide a device that reduces phosphorus in a waste stream through microorganism digestion and use for the growing of new cells in the decomposition of organic matter.
It is still another object of the present invention to provide a treatment process that is zone specific and not vessel specific.
It is still another object of the present invention to provide a system design that accommodates a specific flow and specific treatment process.
It is still another object of the present invention to use the toroidal vortex action of the RCAS system for the reduction of the number of pathogenic organisms within wastewater.
It is still another object of the present invention to provide an apparatus and method that allows for chemical oxidation of an aqueous solution.
It is still another object of the present invention to provide a means for the homogenization of a microorganism colony and the substrate upon which the colony feeds.
It is still another object of the present invention to provide for the disbursement of a large microorganism floc into a smaller microorganism floc.
It is still another object of the present invention to cause the entire microorganism floc including the center to remain aerobic.
It is still another object of the present invention to provide a high concentration of dissolved oxygen in an aerobic process.
It is still another object of the present invention to provide an alternative to the cost and need for wastewater lagoons.
It is yet a further object of the present invention to overcome the deficiencies of known wastewater treatment systems and methods.
In order to represent the applications for, and capabilities of, the present invention, raw influent of municipal wastewater is exampled as the aqueous waste to be treated. However the embodiments of the apparatus and method of the present invention can be implemented to treat a variety of wastes.
The term aeration as it pertains to the present invention means the addition of a secondary fluid flow (liquid or gas) into a primary fluid flow (liquid or gas).
The present invention is able to treat organic matter of wastewater by providing intense aeration by means of an RCAS (Re-Circulating Aeration System) which gives increased oxygen transfer efficiencies that result in increased microorganism oxygen uptake rates and the fractionalizing, shredding and homogenizing of organic matter causing virtually 100% digestion of the organic matter. This is a significantly more effective use of processing energy as compared with traditional treatment methods using traditional aeration such as diffused aeration. The present invention also reduces or eliminates many traditional energy-consuming devices such as primary clarification equipment, anaerobic digestion equipment, aerobic digestion equipment, primary treatment lagoons, incineration furnaces and related equipment, sludge-thickening equipment and sludge-hauling equipment.
The present invention enables a more efficient and complete digestion of organic matter in the wastewater. The organic matter portions of the wastewater (total BOD) are treated in a first aerobic reactor zone and a second aerobic reactor zone by use of aeration, and in an anaerobic conditioner zone and an anoxic selector zone where the wastewater is kept in a condition in which the aquatic environment does not contain sufficient dissolved molecular oxygen for easy microorganism respiration, which can also be called an oxygen-deficient condition. This oxygen-deficient condition generally refers to an environment in which chemically bound oxygen, such as nitrate, is present. Aggressive digestion of the organic matter is accomplished in the anaerobic conditioner zone, first aerobic reactor zone, anoxic selector zone and second aerobic reactor zone.
In accordance with one form of the present invention a process for the treatment of an aqueous solution containing waste includes the steps of:
providing an influent wastewater stream to an anaerobic conditioner zone within which aqueous total solids are recirculated, mixed and kept in suspension;
providing low oxygen level mixed liquor suspended solids from an anoxic selector zone to the anaerobic conditioner zone to maintain a low dissolved oxygen level within the anaerobic conditioner zone;
providing an outflow from the anaerobic conditioner zone to a first aerobic reactor zone, the anaerobic conditioner zone outflow being mixed in the first aerobic reactor zone with return activated sludge from a clarification zone whereby contents of the first aerobic reactor zone are recirculated and aerated, and whereby settleable solids present in the contents of the first aerobic reactor zone are fractionalized, thereby decomposing and oxidizing the solids and other organic matter and accumulating inert solids;
discharging the accumulated inert solids from the first aerobic reactor zone;
providing an outflow of aqueous solution from the first aerobic reactor zone to the anoxic selector zone wherein the aqueous solution in the anoxic selector zone is recirculated and mixed;
transferring a first portion of the anoxic selector zone aqueous solution corresponding to the low oxygen level/mixed liquor suspended solids to the anaerobic conditioner zone, and a second portion of the anoxic selector zone aqueous solution to a second aerobic reactor zone;
recirculating and aerating aqueous solution contained in the second aerobic reactor zone whereby settleable solids become fractionalized thereby decomposing and oxidizing suspended solids and other organic matter;
providing a first portion of the second aerobic reactor zone aqueous solution to the first aerobic reactor zone;
providing a second portion of the second aerobic reactor zone aqueous solution to the clarification zone to settle or separate solids from the aqueous solution contained therein;
providing the settled or separated solids from the clarification zone, corresponding to return activated sludge, to the first aerobic reactor zone;
providing aqueous solution of the clarification zone to a filtration zone to settle or separate solids from the aqueous solution provided thereto; and
transferring a liquid portion of an outflow of the filtration zone to a discharge receptacle, and the settled or separated solids portion of the outflow of the filtration zone to the influent wastewater stream for re-processing.
In accordance with another form of the present invention, a process for the biological treatment of an aqueous solution containing waste to reduce organic material, nitrogen and phosphorus, includes the steps of:
providing an influent wastewater stream, which includes microorganisms, to an anaerobic conditioner zone within which aqueous total solids are recirculated, mixed and kept in suspension, wherein a first stage of luxury phosphorus uptake is accomplished by regulating a flow of low oxygen level mixed liquor suspended solids from an anoxic selector zone to the anaerobic conditioner zone to maintain a low dissolved oxygen level within the anaerobic conditioner zone;
providing an outflow from the anaerobic conditioner zone to a first aerobic reactor zone, the anaerobic conditioner zone outflow being mixed in the first aerobic reactor zone with return activated sludge received from a clarification zone whereby contents of the first aerobic reactor zone are recirculated and aerated and whereby nitrification occurs and settleable solids present in the contents of the first aerobic reactor zone are fractionalized, thereby decomposing and oxidizing suspended solids and other organic matter along with enhancing a second stage of luxury phosphorus uptake and accumulating inert solids;
discharging the accumulated inert solids from the first aerobic reactor zone;
providing an outflow of aqueous solution from the first aerobic reactor zone to the anoxic selector zone wherein the aqueous solution in the anoxic selector zone is recirculated and mixed, and causing a low oxygen environment to exist within the anoxic selector zone such that denitrification and release of biological phosphorus occurs along with the consumption of organic matter contained within the aqueous solution;
transferring a first portion of anoxic selector zone aqueous solution corresponding to low oxygen level/mixed liquor suspended solids to the anaerobic conditioner zone and a second portion of the anoxic selector zone aqueous solution to a second aerobic zone, at least the second portion of the anoxic selector zone aqueous solution being rich in microorganisms and nutrients;
re-circulating and aerating aqueous solution contained in the second aerobic reactor zone whereby nitrification occurs and settleable solids become fractionalized and shredded thereby decomposing and oxidizing suspended solids and other organic matter, and further enhancing the second stage of luxury phosphorus uptake resulting in a consumption of a large amount of phosphorus by the microorganisms;
providing a first portion of the second aerobic reactor zone aqueous solution to the first aerobic reactor zone;
providing a second portion of the second aerobic reactor zone aqueous solution to the clarification zone to settle or separate solids from the aqueous solution provided thereto;
providing the settled or separated solids from the clarification zone to the first aerobic reactor zone as return activated sludge;
providing aqueous solution of the clarification zone to a filtration zone to settle or separate solids from the aqueous solution provided thereto; and
transferring a liquid portion of an outflow of the filtration zone to a discharge receptacle and the settled or separated solids portion of the outflow of the filtration zone to the influent wastewater stream for re-processing.
In accordance with another form of the present invention, apparatus for the treatment of an aqueous solution containing waste includes:
an anaerobic conditioner zone fluidly coupled to an inlet, the anaerobic conditioner zone receiving an influent wastewater stream through the inlet, the anaerobic conditioner zone re-circulating the wastewater contained therein such that aqueous total solids are kept in suspension, the anaerobic conditioner zone receiving a flow of low oxygen level mixed liquor suspended solids from an anoxic selector zone to maintain a low dissolved oxygen level within the anaerobic conditioner zone;
a first aerobic reactor zone fluidly coupled to the anaerobic conditioner zone, the first aerobic reactor zone receiving an outflow of the anaerobic conditioner zone which is mixed with return activated sludge received from a clarification zone whereby contents of the first aerobic reactor zone are recirculated and aerated and whereby settleable solids become fractionalized thereby decomposing and oxidizing suspended solids and other organic matter, the first aerobic reactor zone accumulating inert solids, the accumulated inert solids being discharged from the first aerobic reactor zone;
an anoxic selector zone fluidly coupled to the anaerobic conditioner zone and the first aerobic reactor zone, the anoxic selector zone receiving an outflow of aqueous solution from the first aerobic reactor zone, aqueous solution within the anoxic selector zone being recirculated and mixed, a first portion of the anoxic selector zone aqueous solution, corresponding to the low oxygen level/mixed liquor suspended solids, being provided to the anaerobic conditioner zone;
a second aerobic reactor zone fluidly coupled to the anoxic selector zone and the first aerobic reactor zone, the second aerobic reactor zone receiving a second portion of the anoxic selector zone aqueous solution wherein the aqueous solution within the second aerobic zone is recirculated and aerated whereby settleable solids become fractionalized, a first portion of the aqueous solution of the second aerobic reactor zone being provided to the first aerobic reactor zone;
a clarification zone fluidly coupled to the second aerobic zone and the first aerobic zone, the clarification zone receiving a second portion of the second aerobic reactor zone aqueous solution, whereby settling or separating and capturing of solids from the aqueous solution occurs, and the settled solids, corresponding to return activated sludge, are provided to the first aerobic reactor zone; and
a filtration zone fluidly coupled to the clarification zone, the inlet, and an outlet, the filtration zone receiving an outflow from the clarification zone to separate solids from the liquid portion of the contents of the clarification zone, a first portion of the contents of the filtration zone, which corresponds to effluent, being provided to the outlet, and a second portion of the contents of the filtration zone, which corresponds to separated solids, being provided to the inlet and being combined with the influent wastewater stream for re-processing.
These and other objects, features and advantages of the present invention will become apparent from the following detailed description of preferred embodiments which is to be read in connection with the accompanying drawings.